It's truly unfortunate how under-discussed Etymotic is in the headphone community. The Etymotic ER4P was my first audiophile headphone purchase 11 years ago, and I STILL use it to this day. I bought the ER4XR 6 months ago when it was newly-released, and it became my new favourite headphone. The small bass boost really made a difference in filling out music, and the cable is much softer and pliable than the old models, which make it more comfortable to wear, and there's less noise when it brushes against your clothes.
I have a few pairs of open-backed headphones, and I like them, but these are a must for portability and travel— wearing these on a plane is amazing, even successfully blocking out crying babies next to you! And while they're very flat and neutral in their response, that also means they're very easy to EQ.
But that being said, this isn't a good deal and I'd recommend getting them off Amazon.